Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
325 FXUS63 KGLD 290312 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 912 PM MDT Tue May 28 2024 .KEY MESSAGES... - Chance for severe weather and flooding throughout the week. Confidence in specific hazards change each day, but a very active pattern is expected. && .UPDATE... Issued at 910 PM MDT Tue May 28 2024 Severe thunderstorm watch 347 has been allowed to expire on time as the severe threat has waned. We continue to watch heavy rainfall across Greeley and Wichita counties and another potential round of storms moving again into western portions of Kit Carson and Yuma counties; currently anticipating these to remain sub severe. && .UPDATE... Issued at 722 PM MDT Tue May 28 2024 Severe Thunderstorm Watch 347 continues to look on track through 03Z. Two continued longer lived left mover supercells continue to trek to the northeast across Kit Carson county and southern Yuma county. Larger area of precipitation to the south isn`t looking as robust as early as the environment may be a bit worked over. Will continue to watch for torrential rainfall potential and perhaps some localized hydro issues especially in low lying areas. Did introduce some patchy fog into the forecast due to the continued SSE moisture advection, recently saturated boundary layer and lighter winds around sunrise. Am targeting locales south of the Interstate for this potential as this appear to be where winds will be lightest at. Severe potential continues to remain on track as a broken line of storms looks to move off the Palmer Divide and moves east into the area. Hail and wind threat currently look to be the main threats similar to today. && .SHORT TERM /THROUGH TONIGHT/... Issued at 153 PM MDT Tue May 28 2024 Morning and early afternoon convection occurred along narrow band of 700 mb frontogenesis which has moved southeast of the area. Additional convection is expected later this afternoon and into this evening as a shortwave trough moves out of the Rockies. There is also a weakening cold front moving out of Nebraska and possible outflow boundary from earlier convection. CAMs show best chances for additional storms will generally be south of a Joes, Colorado, to Scott City, Kansas, line. Moderate surface based instability early in the evening will quickly weak by around 03z when storms will probably become elevated with persistent MUCAPE. Deep layer shear will also be strongest early in the evening before weakening with time. So all signs point to a marginal severe risk early, but storms weakening after about 03z. Mean precipitation amounts through 06z are around a quarter of an inch, but some locally higher amounts of a little over 1 inch will be possible according to HREF 90th percentile QPF. A few scattered showers and isolated thunderstorms may persist after midnight mainly in eastern areas with additional amounts of less than a tenth of an inch. Low temperatures will be in the 50s. Ridge axis moves east on Wednesday with a pronounced shortwave trough moving into the Rockies in the afternoon. Showers and thunderstorms will initiate on the Front Range and move across eastern Colorado in the afternoon, probably not reaching the Kansas border until after 00z. Most if not all of the area will be dry until then with high temperatures in the upper 70s to around 80. Broken line of showers and thunderstorms will then move west to east across the area Wednesday night. Initial line may have a hail/wind threat early in the evening before transitioning to mainly a wind threat further east later in the evening. 6-hour mean precipitation amounts are around a quarter of an inch through 06z, with some locally heavier amounts of 1 to 1.25 inches possible generally north of Interstate 70. Amounts between 06-12z will be lighter, though can`t completely rule out some local amounts in eastern areas approaching 1 inch. Low temperature will be in the 50s to around 60. Showers and thunderstorms may persist into Thursday morning as the upper trough axis and accompanying surface cold front slowly move through the area. Should see additional post frontal development during the afternoon as another vorticity lobe rotates around the main low in the northern plains. Not sure how much instability can recover given the morning clouds and precipitation, but there is some potential for severe storms with any clusters propagating off the higher terrain to the west, with the main hazard being wind. Deep layer shear tops out at around 30 kts which may limit more organized convective threat. However, as storms move further east Thursday night the 0-6 km winds diminish to 10 kts or less, suggesting slow storm motions. Mean 6-hour QPF through 06z for areas east of Highway 25 around a half inch but higher percentiles are between 1-2 inches. There is some concern for flooding given these parameters and antecedent rainfall the previous few days. High temperatures will be in the 70s and lows in the 50s. The pattern does not change much on Friday. Showers and thunderstorms linger in the morning, mainly in eastern areas, then redevelop in the afternoon with another wave rotating around the main upper low now in central Canada and low level upslope flow. Instability is weak to moderate, highest in Colorado, but there is an increase in deep layer shear to 40-50 kts, sufficient for a severe risk with any discrete cells in the afternoon and evening hours. However, QPF is much lower compared to previous days which may mitigate any additional flooding concerns. Not much change in temperatures with highs in the 70s and lows in the 50s. && .LONG TERM /WEDNESDAY THROUGH TUESDAY/... Issued at 153 PM MDT Tue May 28 2024 Looking ahead to the weekend, pattern does not really change for either Saturday or Sunday. Southwest flow aloft is forecast with embedded waves providing synoptic scale lift for precipitation. Sufficient instability and shear for a risk of severe storms is also indicated. On Sunday, may see a dry line and front come into play, but difficult to pin down exact locations of either at this time range, but better chances for precipitation may be pushed a bit east on Sunday with the dry line. Temperatures warm up both days, with highs in the 80s on Saturday and 80s and 90s by Sunday. Lows will be mainly in the 50s. For Monday and Tuesday, another system will cut off an upper low over the northern plains with shortwave energy rotating around it over the central plains both days, which is more or less a repeat of the current pattern. Until there is a more substantial pattern change, possibly mid to late week with a building ridge, shower and thunderstorm chances will continue. Temperatures show little variation with highs in the 80s and lows in the 50s. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 440 PM MDT Tue May 28 2024 Storms are developing fairly quickly across eastern Colorado and may impact the KGLD terminal near the start of the period. Mean flow is to the SE which makes me lean towards the terminal not being impacted but will need to watch on a either a left mover the northeast or additional upscale growth; so an AMD may be needed. Storm threat should end around 04Z, will then need to watch for stratus or fog potential around sunrise due to the newly saturated boundary layer and continued moisture advection from the ESE. Winds will become breezy from the south Wednesday near 30 knots at times, will then need to watch to for additional storms just after the end of the period. && .HYDROLOGY... Issued at 256 AM MDT Tue May 28 2024 Highly efficient moisture return looks to begin late Tuesday night and continue into the end of the workweek via the 850 mb LLJ. This moist conveyor belt will cause PWATS to increase above 1 inch starting Wednesday and potentially remain that way until Saturday. The highest values will be in the eastern CWA, but the majority of the Tri-State area will have a good chance (60%+) at seeing PWATS above 1 inch. Throughout this active pattern, a high melting layer is also expected, generally 11,000-15,000 feet agl. Tuesday does have a very low concern for flooding (~5%) as clusters of storms could produce multiple rounds of precipitation over the same area. This precipitation is expected to remain more in the southern CWA where conditions have been dry, so the ground will likely soak it right up. Wednesday and Thursday are currently the best days for storms to create heavy rainfall that could lead to rate-driven flash flooding and duration-driven areal flooding. Friday and Saturday are also at risk for flooding potential due to a combination of efficient rain producing storms and potentially multiple days of heavy rain saturating the soil. Current confidence in localized flooding occurring in the latter half of the week is around 10-15%. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ UPDATE...Trigg SHORT TERM...KAK LONG TERM...CA/KAK AVIATION...Trigg HYDROLOGY...